Dynamic mechanical behavior of syntactic iron foams with glass microspheres

In this work, the mechanical behavior of syntactic foams made of hollow glass microspheres mixed in an iron matrix was investigated. This type of material is interesting since, when compared to other types of metal foams, it offers greatly increased quasi-static compressive strength, though at lower maximum porosity and thus higher density. Moreover it maintains the advantages and useful properties of metal foams such as thermal and environmental resistance. In particular, the strain-rate sensitivity response was studied. The experimental characterization was performed by means of compression tests at three strain-rate levels: at the highest strain-rate level a SHPB was used. Type and content of glass microspheres were also studied. The experimental results showed that the compression behavior of syntactic foams, similarly to the other types of foams, is strongly affected by all the examined factors. For what concerns the strain-rate, it was found to increase material characteristics in almost all cases. The influence of the matrix behavior on the composite was identified as the determining parameter in this respect. In order to evaluate the results obtained with the described tests campaign, the experimental data were further elaborated by means of an empirical analytical strain-rate sensitive model. The dependency of the material response on model parameters was widely discussed.